1. Field of the Invention
This invention relates to a drive system for motor vehicles having a motor which has an axis that is transverse to the direction of travel of the vehicle and either a manually operable change-speed transmission which is disposed substantially beside the motor, or an automatic change-speed transmission which is coaxial to the drive shafts of the front axle, wherein the change-speed transmission is operatively connected to the front axle differential of the vehicle, optionally via idler gears, and is operatively connected by an angle drive to a shaft which leads to and is operatively connected to the rear axle.
2. Description of the Prior Art
Such a drive system comprising a manually operable change-speed transmission disposed beside the motor is known, e.g., from Published German Application 32 16 203. To permit the rear axle to be driven at all times an interaxle differential is required, which is connected to both axles. That interaxle differential consists of a planetary gear train having three torque-transmitting members so that a fixed ratio is maintained between the torques for driving the front and rear axles and said interaxle differential must be restrainable so that the vehicle can be driven even when one wheel is spinning. Another known drive system (Published German Application No. 32 23 836) comprises an automatic change-speed transmission which is coaxial to the shaft for driving the front axle and does not require an interaxle differential connected to the front and rear axles but the shaft connected to the rear axle of the vehicle must be adapted to be disconnected so that the rear wheels will not always be driven. On the other hand the front axle differential is driven via a planetary gear train which has three torque-transmitting members, one of which is an internal gear that is held against rotation on the housing. That planetary gear train serves to drive the front axle differential at a fixed transmission ratio. None of the known drive system is so designed that the essential parts used to drive the front and rear axles can be the same regardless of the type and arrangement of the change-speed transmission.